J. Sprengard, L. Christy
General Nano, LLC,
Keywords: EMI shielding, lightning strike protection, carbon nanotubes, lightweight, multifunctional, conductive, wire and cable, composites
Summary:A new class of lightweight, non-metallic, multifunctional material that aerospace and defense prime contractors and integrators are evaluating to improve size, weight and power of weapon systems has been developed in commercially available volumes. Applications in testing include multifunctional composites, lightweight wire and cable, EMI shielding, radiation protection, ice protection, composite repair, thermal calibration, and additive manufacturing. This new materials solution is targeted as an alternative to heavy metals, particularly expanded metal foils, braids, and tapes. Weight savings is the driving force – this new carbon nanotube based material is 1/10th the weight of tradition metals. General Nano has successfully demonstrated continuous manufacturing of carbon nanotube based nonwovens. General Nano is the largest manufacturer of continuous carbon nanotube sheets, capable of producing 12’ wide by 100+ feet long continuous CNT nonwoven rollstock. To date, General Nano has shipped 2500+ feet of CNT rollstock to various customers for such applications as structural and electrical enhancement of carbon fiber composites to deicing of UAV leading edges. General Nano has demonstrated improved G1C properties of IM7/977-3 composite systems with improved electrical conductivity. This multi-functionality allows for improved mechanical and electrical properties simultaneously, reducing or even eliminating the need to add metallic products back into the carbon fiber composite. Recently, General Nano has formulated a carbon nanotube based conductive shield tape, which rivals the shielding properties of convention Ag/Cu metallic braids. Using this CNT based shielding tape, General Nano has already demonstrated a 25% weight savings against a conventional double braid (Ag/Cu) shielded RG-316 coaxial cable. General Nano predicts that it is possible to achieve 50% weight savings by eliminating these double braids and replacing them with CNT based shields; 75% would be achievable by replacing both the Cu conductor and shields with CNT based materials. This CNT shield tape is not limited to coaxial cable use; this novel lightweight material can be integrated into the cable as a direct replacement to the shielding (metallic braid) of a MIL-STD-1553 twisted pair cable, for wire harnesses, as well as other wire and cable shielding needs. In addition, the CNT nonwoven can be used as a surface ply for panel shielding, shielded enclosures, ESD, or even lightning strike protection. Other applications of interest include the use of CNT nonwovens for use in energy storage, antennas, EMI gaskets, deicing, composite repair, out-of-autoclave composite curing, heat sinks, ballistic armor, water filtration, and sensors.